Various kinds of portable electronic devices such as a notebook personal computer (PC) and a PDA are developed. This kind of electronic device is configured to operate with any one of an AC power source and a battery in view of not only mobile use where no AC commercial power supply is provided but also indoor use in, e.g., office and home. The used battery is usually a rechargeable secondary battery such as a nickel-metal hydride battery and a lithium ion battery.
In many cases, whether a commercial power supply or a battery is to be used is determined by whether an AC adapter is connected or not. When the AC adapter is connected to the PC, the power supply of the PC is switched from the battery to the AC adapter, and the battery is charged with the AC adapter. While the AC adapter is detached from the PC, the battery is used as a driving power supply.
In recent years, the amount of electric power demand is more than the amount of electric power provided from a power plant of an electrical supply company, and it is considered that this may cause major power outage. To avoid this, scheduled outage or rolling blackout is considered to be carried out by the electrical supply company to stop/resume electric power supply in each of certain areas in turn. Among household electric devices, a television receiver apparatus consumes relatively large electric power. Therefore, reduction of electric power demand by the television receiver apparatus is considered. For example, like a conventional PC, a television receiver apparatus having a battery therein is considered, so that the television receiver apparatus operates with either the AC commercial power supply or the battery.
However, even though the battery control of the conventional PC is applied to the television receiver apparatus without any modification, the electric power demand cannot be reduced greatly.